Spark plug



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Jan. 29, 1929.

1,700,644 c. M. PEARSAEL SPARK PLUG Filed March 29, 1927 Patented Jan. 29, 1929.

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CHARLES 1vr. PEABSALL, or nrnenwoon nnw JE'nsE'Ya moans SPARK PLUG.

Application filed March 29, 1927; I Serial no. 179,356.

This inventionrelates to a spark plug, and

i has for its primary object the arrangement in a unitary article ofia spark construction and a device whereby the spark plug may be partially orentirely short-circuited.

An object of the invention is the construction of'a spark plug incorporating in its construction a movable contact element whereby the distance between the electrodes of the spark plugs may be bridged.

Another object of the inventionis the construction of a spark plug having a detach-i able contact element, by means of which the spark plug may be tested. 7 c

A feature of the invention is the simplified construction of the contact element and mode of connection to the spark plug proper.

With these and otherobjects in view, my

invention will be better understood from a description of the same when taken in connection with the accompanying drawing, wherein a Figure 1 is a side elevation of a spark plug constructed in accordance with my invention, showing the contact in operative position;

Figure 2 is a similar view with the contact in its other position;

Figure 3 is a top plan view;

Figure 4: is a vertical sectional view through the contact;

Figure 5- is an enlarged fragmentary view of the lower portion of the contact.

Again referring to the drawing illustrating one of the many constructions of my invention, the numeral 1 designates the central electrode of the spark plug supported within the shell 2 forming the outer electrode. This outer electrode or shell 2 is provided with an annular. series of inclined holes 3 for frictional engagement with the contact of a special construction so as to not only reduce materially the cost of manufacture but to facilitate the operative association of the contact with the various electrodes of the spark plug.

One manner of accomplishing this desired result is illustrated in the drawing as a strip 4 bent to have an intermediate ofl-set portion 5 and an annularly extending end portion 6 and a tang 7 at its upper end for arrangement in a knob 8 of insulating material. The contactstrip intermediate its off-set portion is provided with a flattened contact or contact surface 9 so disposed as to be capable of moving into engagement withthecentral electrode,.as shown in Figure 1.: To enable the contact'strip to swing in the arc of a circle and to eflectively hold the contact in position against vibration, the lower end .6 is split, as indicated at 10, to provide the prongs 11, each provided with a cam wall 12 to facilitate the insertion of the end into the hole, and due to the expansible action of the prongs the frictionalengagement between the prongs and the wall'o'f the associated'hole will effectively hold the contact in any one of its adjusted positions and besides effective.-

ly prevent vibration of the device.

With the construction of spark plug as illustrated, it will be appreciated that the; plug can be veryeasily tested and'short-.

- circuited in such amanner that the location of the contact will not interfere with'the manners than illustrated, as the main feature of my invention is the combination of parts whereby a contact may be made a permanent part of the plug and arranged tobe easily manipulated into'and out of contacting relation with both electrodes and, therefore, I do not desire to be limited in any manner except asset forth in the appended claims.

I claims-.- I" i 1. A contact element for use with a spark plug having an outer electrode provided with a hole nearly parallel to the plug axis, said contact element having one end split for insertion into and adapted to have frictional engagement with said hole, said element 7 further having an offset portion adapted to engage the central electrode of the plug when the element is rotated within the hole associated therewith.

2. A contact element for use with a spark plug having an outer electrode provided with a hole nearly parallel-to the plug axis, said contact element having one end split for in 5 sertion into and adapted to have frictional engagement with said hole, said element further having an offset portion adapted to engage the central electrode of the plug when the element is rotated within the hole associated therewith, and an insulation knob secured to said elementat the end opposite the slit for moving the element. 7

In testimony whereof I affix my signature.

CHARLES v M. PEARSALL. 

